"orless", logical negation and FTA

saeaadl / emv2

AADL Error Model V2 annex language

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"orless", logical negation and FTA #15

Open buzden opened 8 years ago

buzden commented 8 years ago

The orless operator (using out definition) implies the not operator (see #13 and #14). A Fault Tree does not contain not operators.

How the orless operator should be processed in FTA? Is the orless operator supposed to be used only in “recover/repair” transitions? Should “recover/repair” transitions be marked somehow to distinguish them from “error” transitions?

reteprelief commented 8 years ago

I inherited the orless from Steve Vestal's original error model in MetaH. If I remember correctly he wanted to get at the "all but" by expressing the negation, i.e., how many are error free. I agree there is an issue as FTA does not have a NOT. I believe we can eliminate "orless" with the introduction of (all - k) ormore.

jjhugues commented 3 years ago

Issue #7 introduces (all - k) suppressing orless might be seen as a loss of capabiltiy.

[ ] Do we want to keep both and document they are equivalent?
[ ] Suppress the orless and have only (all - k) ?
[ ] A specific not operator seems unnecessary, no real demand